Macromolecular characterization of disease resistant red wine varieties (PIWI)


AIM: Pilzwiderstandsfähige (PIWI) are disease resistant Vitis vinifera interspecific hybrid varieties that are receiving increasing attention for ability to ripen in cool climates and their resistance to grapevine fungal diseases. Wines produced from these varieties have not been characterized, especially regarding their macromolecular composition. This study characterised and quantified colloid-forming molecules (proteins, polysaccharides and phenolics) of red PIWI wines produced in the UK.

In 2019 6 wines were made from the PIWI varieties Rondo, Cabernet Jura, Cabernet Cortis, Cabernet Noir, Regent and Cabertin grown at the Plumpton Rock Lodge Vineyard in Sussex (UK) and harvested at similar level of maturity (TSS, pH and TA). All juice was chaptalized to the same potential alcohol of 12%. Small scale winemaking (1L) was performed in quadruplicate using Bodum® coffee plungers to manage maceration [1]. Residual sugar content, pH, and titratable acidity were monitored during fermentation. For finished wines, the protein and polysaccharide content was measured by HPLC-SEC [2], while the total phenolic content was assessed using the Folin-Ciocalteau method [3]. The protein profile of the wines was further investigated by SDS-PAGE [4].

RESULTS: Fermentations (n=24) were all carried out to completion within 8 days. The resulting wines showed important differences in terms of their macromolecular composition. The total polysaccharide content ranged between 903-1217 mg/L and was higher than the typical content of red wines [5]. Also, the total phenolic content was greater than typical red wines from Vitis vinifera (range 2478-4678 mg/L), while the total protein concentration ranged between 114 -152 mg/L. Typical values for red wine range from 10-200 mg/L [4,6]. The electrophoresis analysis showed the presence of pathogenesis-related (defence) proteins, namely chitinases and thaumatin-like proteins in all wines, while a lipid transfer protein (LTP) was found in all wines except for Cabernet Cortis. This is noteworthy as LTPs can cause severe allergenic reactions [7].


Hybrid red grape varieties have the potential to produce wines with chemical and macromolecular composition in line with those from Vitis vinifera. This is a promising result for their future adoption in winegrowing regions subjected to difficult climatic conditions and high disease pressure. However, given that PIWI varieties are likely to over-produce pathogenesis-related proteins as a defence mechanism, future investigations should explore the role of these proteins with regard to colloidal and colour stability and allergenic potential.


Publication date: September 16, 2021

Issue: Macrowine 2021

Type: Article


Edward Brearley

Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padova, Italy,Matteo MARANGON, Department of Agronomy, Food, Natural Resources, Animals and Environment, University of Padova, Italy Daniel JACKSON, Plumpton College, England Tony MILANOWSKI, Rathfinny Wine Estate, England Gregory DUNN, Plumpton College, England

Contact the author


disease resistant, piwi, red wines, proteins, polysaccharides, phenolics, colloids


Related articles…

Physiological and growth reaction of Shiraz/101-14 Mgt to row orientation and soil water status

Advanced knowledge on grapevine row orientation is required to improve establishment, management and outcomes of vineyards on terroirs with different environmental conditions (climate, soil, topography) and in view of a future change to more extreme climatic conditions. The purpose of this study was to determine the combined effect of row orientation, plant water status and ripeness level on the physiological and viticultural reaction of Shiraz/101-14 Mgt.

Effects of mechanical leafing and deficit irrigation on Cabernet Sauvignon grown in warm climate of California

San Joaquin Valley accounts for 40% of wine grape acreage and produces 70% of wine grape in California. Fruit quality is one of most important factors which impact the economical sustainability of farming wine grapes in this region. Due to the recent drought and expected labor cost increase, the wine industry is thrilled to understand how to improve fruit quality while maintaining the yield with less water and labor input. The present study aims to study the interactive effects of mechanical leafing and deficit irrigation on yield and berry compositions of Cabernet Sauvignon grown in warm climate of California.

The effects of cane girdling on berry texture properties and the concentration of some aroma compounds in three table grape cultivars

The marketability of the table grapes is highly influenced by the consumer demand; therefore the market value of the table grapes is mainly characterized by its berry size, colour, taste and texture. Girdling could cause accumulation of several components in plants above the ringing of the phloem including clusters and resulting improved maturity. The aim of the experiments was to examine the effect of girdling on berry texture characteristics and aroma concentration.

Application of a fluorescence-based method to evaluate the ripening process and quality of Pinot Blanc grape

The chemical composition of grape berries at harvest is one of the most important factors that should be considered to produce high quality wines. Among the different chemical classes which characterize the grape juice, the polyphenolic compound, such as flavonoids, contribute to the final taste and color of wines. Recently, an innovative non-destructive method, based on chlorophyll fluorescence, was developed to estimate the phenolic maturity of red grape varieties through the evaluation of anthocyanins accumulated in the berry skin. To date, only few data are available about the application of this method on white grape varieties.

Different yield regulation strategies in semi-minimal-pruned hedge (SMPH) and impact on bunch architecture

Yields in the novel viticulture training system Semi-Minimal-Pruned Hedge (SMPH) are generally higher compared to the traditional Vertical Shoot Positioning (VSP). Excessive yields have a negative impact on the vine and wine quality, which can result in substantial losses in yield in subsequent vintages (alternate bearing) or penalties in fruit quality. Therefore yield regulation is essential. The bunch architecture in SMPH differs from VSP. Generally there is a higher amount but smaller bunches with lower single berry weights in SMPH compared to VSP.